In The Beatles’ catalog, “Hey Bulldog” is a bridge between the psychedelic excesses of 1967 and the rock and roll revivalism they would pursue on the White Album and Let It Be.

Written by John Lennon, the song is a straightahead rocker featuring a seductive boogie-style riff and some excellent aggressive lead guitar work. The Beatles recorded the track at the same session that produced “Lady Madonna,” a song that, like “Hey Bulldog,” shows them digging back to their roots.

Unlike Sgt. Pepper’s and Magical Mystery Tour, the production on “Hey Bulldog” is suitably devoid of any frills or sonic frippery. The song was originally titled “Hey Bullfrog,” but while recording vocals with Lennon, Paul McCartney began imitating a dog’s bark as the tape was rolling, inspiring Lennon to change the lyrics on the spot, and subsequently the title as well.

Thanks to a crew that was on hand to film The Beatles in the recording studio, footage exists of the group recording “Hey Bulldog” (see below). (The footage was originally edited together for the “Lady Madonna” promotional video, though it has since been recut to fit “Hey Bulldog.”)

In the film, George Harrison can be seen playing his cherry-finish Gibson SG, and Lennon can be viewed playing a bit of lead work on the instrument (whether he actually played the guitar on the track isn’t clear) in addition to strumming his Epiphone Casino and playing piano. McCartney plays his Rickenbacker 4001S bass and bangs together a pair of tambourines, one with a head and another without.

The authorship of the stinging guitar solo has been up to debate over the years — some say it recalls McCartney’s solo performance on “Taxman” — but engineer Geoff Emerick says it was definitely played by Harrison.

“[It was] one of the few times that he nailed it right away,” he wrote in his 2006 memoir, Here, There and Everywhere. “His amp was turned up really loud, and he used one of his new fuzz boxes, which made his guitar absolutely scream.”

With its infectious riff and the Beatles’ tremendously confident handling of the song, “Hey Bulldog” could have easily been selected for either side of a single release. Surprisingly, it languished in the vault at Abbey Road for another year until the Beatles offered it to the producer of the Yellow Submarine film.

Such were The Beatles’ musical riches that they could afford to let a gem like this gather dust.